This quote comes from Brendan Boyle who works in the IDEO Toy Lab -- a place where ridiculous ideas are encouraged. (By the way, if you're not familiar with the immensely creative industrial design firm IDEO, be sure to watch this.)
Drawing by lineartestpilot.
You really want to create an environment that allows for innovation. Big innovation is right on the edge of ridiculous ideas. You need an environment that isn't quite so judgmental about a ridiculous idea. Sometimes those are the ones that are so close to being the brilliant ones. If a space that allows for play can help encourage those types of ideas, then you'll come up with some possibly ridiculous but potentially groundbreaking ideas.
The takeaway: put yourself in situations where you can be safe and free to think of crazy ideas. One of them might be pretty great. I'm currently working on a project with a friend that was born out of a joke. I tried to come up with the most ridiculous thing I could to be funny, and after we thought about it for several months we started to realise that a slight alteration made it pretty amazing. Just because something may seem strange and impossible doesn't mean a variation won't be incredible.
IDEO: Big Innovation Lives Right on the Edge of Ridiculous Ideas [The 99 Percent]